U.S. patent application number 10/447273 was filed with the patent office on 2004-04-01 for system with an internal combustion engine, a fuel cell and a climate control unit for heating and/or cooling the interior of a motor vehicle and process for the operation thereof.
This patent application is currently assigned to WEBASTO THERMOSYSTEME INTERNATIONAL GMBH. Invention is credited to Horn, Oliver, Khelifa, Noureddine, Kolb, Alexander.
Application Number | 20040060312 10/447273 |
Document ID | / |
Family ID | 32033846 |
Filed Date | 2004-04-01 |
United States Patent
Application |
20040060312 |
Kind Code |
A1 |
Horn, Oliver ; et
al. |
April 1, 2004 |
System with an internal combustion engine, a fuel cell and a
climate control unit for heating and/or cooling the interior of a
motor vehicle and process for the operation thereof
Abstract
A system with an internal combustion engine which has a heat
transfer circuit, a fuel cell and a climate control unit which is
accommodated in the heat transfer circuit of the internal
combustion engine. The system has a heat transfer arrangement for
transferring the exhaust heat of the fuel cell to the heat transfer
circuit and a bypass for bridging a segment of the heat transfer
circuit which runs through the internal combustion engine so that,
in the bypassed operating state, an isolated circuit is formed. In
stationary operation, this enables an optimized operating mode
since the internal combustion engine is no longer heated and the
exhaust heat of the fuel cell is fully available for heating
purposes. The climate control unit can have a fuel cell and an
arrangement for transferring the heat produced by the fuel cell to
the vehicle interior has a fan unit by which an air flow can be
produced for cooling the fuel cell and a heating unit which is
powered by the fuel cell and by which the air flow for heating the
vehicle interior can be additionally heated. For cooling or heating
the interior of a motor vehicle, the system can have a cooling
circuit with a compressor, a condenser, an expansion element, and a
first evaporator and an APU or a fuel cell to electrically power
the compressor, and a second cooling circuit a second evaporator,
the second cooling circuit being connected to the first cooling
circuit.
Inventors: |
Horn, Oliver; (Muenchen,
DE) ; Khelifa, Noureddine; (Muenchen, DE) ;
Kolb, Alexander; (Neuried, DE) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW
SUITE 900
WASINGTON
DC
20004-2128
US
|
Assignee: |
WEBASTO THERMOSYSTEME INTERNATIONAL
GMBH
Stockdorf
DE
|
Family ID: |
32033846 |
Appl. No.: |
10/447273 |
Filed: |
May 29, 2003 |
Current U.S.
Class: |
62/244 ;
165/42 |
Current CPC
Class: |
F25B 2400/075 20130101;
Y02B 90/10 20130101; B60H 1/00428 20130101; Y02T 10/88 20130101;
Y02E 60/50 20130101; B60H 1/323 20130101; H01M 2250/405 20130101;
B60H 1/03 20130101; H01M 2250/20 20130101; F25B 27/00 20130101;
B60H 1/143 20130101; F25B 5/02 20130101; F25B 2327/001 20130101;
H01M 8/04014 20130101; B60H 1/3222 20130101; Y02T 90/40
20130101 |
Class at
Publication: |
062/244 ;
165/042 |
International
Class: |
B60H 003/00; B61D
027/00; B60H 001/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 29, 2002 |
DE |
102 23 949.5 |
Dec 12, 2002 |
DE |
102 58 195.9 |
Dec 12, 2002 |
DE |
102 58 196.7 |
Claims
What is claimed is:
1. System comprising an internal combustion engine which has a heat
transfer circuit, a fuel cell, and a climate control unit which is
accommodated in the heat transfer circuit of the internal
combustion engine, wherein a heat transfer means is provided for
transferring exhaust heat of the fuel cell to the heat transfer
circuit and a bridging means is provided for bridging a segment of
the heat transfer circuit which runs through the internal
combustion engine so that in a bridged operating state, an isolated
circuit is formed.
2. System in accordance with claim 1, wherein the heat transfer
means comprises a segment of the heat transfer circuit which is
routed via the fuel cell.
3. System in accordance with claim 1, wherein the heat transfer
means are formed by the exhaust gas of the fuel cell being routed
via a heat exchanger which is accommodated in the heat transfer
circuit.
4. System in accordance with claim 3, wherein the heat transfer
means are formed by the fuel cell being connected to an afterburner
for afterburning of exhaust gas of the fuel cell, and wherein the
exhaust gas of the afterburner is routed via a heat exchanger which
is accommodated in the heat transfer circuit.
5. System in accordance with claim 3, wherein at least one second
heat exchanger is provided between the fuel cell and the heat
exchanger for preheating of at least one feed air and fuel for the
fuel cell.
6. System in accordance with claim 1, wherein the climate control
unit comprises a heat exchanger for heating a vehicle interior, an
electrical heater which is connected to the fuel cell for power
supply, and a first evaporator of a cooling circuit.
7. System in accordance with claim 6, wherein the cooling circuit
comprises an electrically driven compressor which is connected to
the fuel cell for power supply.
8. System in accordance with claim 6, wherein the isolated circuit
has a heat exchanger for dissipating heat from the heat exchange
circuit.
9. System in accordance with claim 7, wherein the cooling circuit
comprises an additional compressor which is mechanically driven by
the internal combustion engine, the electrically driven compressor
and the mechanically driven compressor being redundant and being
able to be turned on and off individually.
10. System in accordance with claim 6, wherein two component
circuits are formed in the cooling circuit, the first component
circuit being formed by the first evaporator, a condenser and an
electrically driven compressor, and the second component circuit
being formed by a second evaporator, the condenser and a compressor
which is mechanically driven by the internal combustion engine.
11. System in accordance with claim 10, wherein the electrically
driven compressor and the compressor which is mechanically driven
by the internal combustion engine are connectable in parallel such
that the compressor which is mechanically driven by the internal
combustion engine is connected on an input side to the first and
the second evaporator.
12. System in accordance with claim 6, wherein two component
circuits are formed in the cooling circuit, the first component
circuit being formed by the first evaporator, a condenser and a
hybrid compressor which can be mechanically driven by the internal
combustion engine and electrically driven, and the second component
circuit being formed by the second evaporator, the condenser and
the hybrid compressor.
13. System in accordance with claim 12, wherein the control unit
has a first operating mode in which the hybrid compressor is
mechanically driven by the internal combustion engine and the two
component circuits are in operation and a second operating mode in
which the hybrid compressor is electrically driven and the
component circuit which contains the second evaporator is turned
off.
14. System in accordance with claim 10, wherein the system is a
truck cab unit for a truck cab having a rear area and a front area,
the first evaporator being assigned to the rear area and the second
evaporator being assigned to the front area.
15. System for cooling and heating the interior of a motor vehicle,
comprising: a first cooling circuit with a first compressor, a
condenser, an expansion element, and a first evaporator, one of an
APU and a fuel cell connected for driving the compressor by means
of electrical energy, at least one second cooling circuit having at
least a second evaporator the at least one second cooling circuit
is connected to the first cooling circuit, and a condenser common
to the first cooling circuit and the second cooling circuit.
16. System as claimed in claim 15, further comprising a second
compressor which is mechanical driven.
17. System as claimed in claim 15, wherein the first compressor is
a hybrid compressor.
18. System as claimed in claim 15, further comprising a second
compressor which is one of mechanical driven and a hybrid
compressor, wherein the first compressor is connected to the first
evaporator, and the second compressor is connected to the second
evaporator.
19. System as claimed in claim 18, wherein the second compressor is
connected to the first evaporator.
20. System as claimed in claim 15, wherein the first compressor is
connected to the second evaporator.
21. System as claimed in claim 15, wherein the first evaporator is
adapted for cooling a sleeping compartment of a commercial vehicle
when a vehicle engine is turned off.
22. System as claimed in claim 15, wherein the second evaporator is
adapted for cooling a driver's compartment of a commercial
vehicle.
23. System as claimed in claim 15, further comprising an electrical
heater and wherein said one of an APU and a fuel cell is a fuel
cell, said fuel cell being connected for powering the electrical
heater when a vehicle engine is turned off.
24. System as claimed in claim 15, wherein said one of an APU and a
fuel cell is a fuel cell, and wherein exhaust heat of the fuel cell
is connected for supplying heat to a cooling circuit of an internal
combustion engine for supplying heat to a vehicle interior
compartment with the engine turned off.
25. System for cooling and heating an interior of a motor vehicle,
comprising: a first cooling circuit with a first compressor, a
condenser, an expansion element, and a first evaporator, one of an
APU and a fuel cell connected for driving the compressor by means
of electrical energy, and at least one second cooling circuit with
at least a second compressor, wherein the at least one second
cooling circuit is connected to the first cooling circuit and
wherein a condenser is provided that is common to the first cooling
circuit and the second cooling circuit.
26. System for cooling and heating an interior of a motor vehicle,
comprising: a first cooling circuit with a compressor, a condenser,
an expansion element, and an evaporator for cooling of the interior
of the motor vehicle during operation of an engine of the vehicle,
a second cooling circuit connected to the first cooling circuit for
cooling the vehicle interior when the vehicle engine is turned off,
wherein said compressor is driven by electrical energy from one of
an APU and a fuel cell for cooling when the vehicle engine is
turned off, and wherein the condenser is common to the first and
second cooling circuits.
27. Climate control unit, comprising: a fuel cell, heat transfer
means for transferring the heat produced by the fuel cell to a
vehicle interior, a fan unit arranged to produce an air flow for
cooling the fuel cell, and an electrical heating unit connect to
receive electrical power from the fuel cell and arranged for
additionally heating the air flow for heating the vehicle
interior.
28. Climate control unit as claimed in claim 27, wherein an
arrangement is provided for diverting part of the air flow out of
the vehicle so as not to heat the vehicle interior.
29. Climate control unit as claimed in claim 27, further comprising
a heat exchanger for transfer of heat between the air flow,
downstream of the fuel cell, and a flow of air which has been
routed into the vehicle interior.
30. Climate control unit as claimed in claim 27, wherein, to cool
the vehicle interior, an electrically operated cooling circuit is
connected to the fuel cell for receiving electrical energy
therefrom.
31. Climate control unit as claimed in claim 30, wherein the
cooling circuit has an electrically driven compressor and a
mechanically driven compressor which are arranged in parallel to
one another.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a system with an internal
combustion engine which has a heat transfer circuit, with a fuel
cell and with a climate control unit which is accommodated in the
heat transfer circuit of the internal combustion engine for heating
and/or cooling of the interior of a motor vehicle, as well as to a
process for operating such systems.
[0003] 2. Description of Related Art
[0004] Systems of the type to which the invention is directed are
used if a fuel cell is to be available as an additional energy
source. The fuel cell is used, first of all, to produce electrical
energy with which the various assemblies of the motor vehicle are
supplied. In the reaction which takes place in the fuel cell, heat
is released which must be dissipated so that the temperature of the
fuel cell does not exceed an allowable upper boundary. Here, it is
conventional to provide a separate heat transfer circuit for the
fuel cell since the fuel cell is made as a separate unit. This
separate execution of the fuel cell has the advantage that the fuel
cell can also be used in stationary operation, and thus, can be
operated independently of the operation of other components of the
vehicle. In stationary operation, for example, the compressor of a
climate control unit, or also a stereo system, light source and all
those energy consumers which are conventionally supplied by the
battery in stationary operation are operated via the fuel cell;
however this is only possible for a relatively short time due to
the limited capacity of the battery.
[0005] The climate control unit which is a component of the system
is conventionally accommodated in the heat transfer circuit of the
internal combustion engine so that the heat produced by the
internal combustion engine can be used to heat the motor vehicle
interior. After a vehicle with an internal combustion engine is
started, it takes a certain amount of time until the climate
control unit can satisfactorily heat the motor vehicle since,
first, the heat transfer circuit of the internal combustion engine
must heat up to such an extent that the heat which the climate
control unit can transfer to the motor vehicle is adequately
available. Moreover, in modern internal combustion engines, there
is the problem that the efficiency of the engine is so high that
the heat transfer circuit can make available only comparatively
little thermal energy for heating of the motor vehicle
interior.
[0006] Auxiliary heaters which additionally heat the cooling liquid
in the heat transfer circuit during the starting phase when the
internal combustion engine has not yet reached its operating
temperature are known. Such a heater is used in order to bring the
internal combustion engine more quickly to its operating
temperature, and on the other hand, to make available heat for the
climate control unit. In the normal operating state, when the
internal combustion engine has reached its operating temperature,
the heat output can be improved by operation of the heater.
[0007] International Patent Application Publication WO 02/075131 A1
discloses a system with an internal combustion engine and a fuel
cell in which the exhaust heat of a fuel cell is used to heat the
internal combustion engine at the same time. For coupling of the
fuel cell and internal combustion engine in heat engineering terms,
it is proposed that either they be structurally joined to one
another so that heat conduction from the fuel cell to the internal
combustion engine takes place, or that there be a common heat
transfer circuit for the fuel cell and internal combustion engine.
Here, it is also proposed that the fuel cell be operated
independently of the internal combustion engine in order to
separately activate an auxiliary air conditioning system, auxiliary
heating or readiness operation. The problem here is that the
internal combustion engine is heated at the same time. While this
improves the starting properties of the internal combustion engine,
it takes a relatively large amount of energy. Especially in
operating situations in which the engine is to be preheated and the
interior is to be heated, not only briefly before starting the
vehicle but, for example, in trucks with sleeping compartments,
where the sleeping compartment must be heated over a long time
interval, the heating of the internal combustion engine demands
considerable amounts of energy.
[0008] On the other hand, for cooling, systems and processes are
known, for example, from published German Patent Application DE 199
27 518 A1 in which the compressor of the cooling circuit is
supplied with energy by a fuel cell in order to thus be able to
carry out stationary air conditioning of the vehicle interior. Use
of a fuel cell as the energy supplier for a compressor has taken
into account problems which occurred in conjunction with other
stationary air conditioning systems, for example, when using latent
storages. Since latent storages occupy a large volume and have a
cooling duration which is greatly limited in time, their use is not
suited in many cases.
[0009] Likewise, according to German Patent Application DE 199 27
518 A1 and the use of a fuel cell proposed there, the problems in
electrical supply of a compressor by the motor vehicle battery
should be solved. This is because, when using the motor vehicle
battery as the energy supplier, the duration of cooling is also
greatly limited, there even being the risk that, after completed
stationary air conditioning, sufficient battery power for starting
is no longer present.
[0010] It is furthermore known that an auxiliary air conditioning
system can also be operated by the internal combustion engine of
the motor vehicle when stopped or by an additional motor. However,
of course, this also has the disadvantages that disturbing noise
occurs, power consumption is high, and burdensome emissions are
formed.
[0011] An air conditioning system in which a compressor is operated
using a fuel cell thus offers a useful starting point for further
developments. If in any case the air conditioning system is
intended for use while driving and also when stopped, there are
requirements which can only be met with difficulty at the same
time. While driving it can often be necessary to dissipate high
thermal output. In contrast, when the vehicle is stopped, for
example, in the air conditioning of the sleeping compartment of a
truck, what is important is to be able to air condition with low
heat dissipation per unit of time over a long interval. Therefore,
if a system is designed for stationary air conditioning, a fuel
cell is chosen with correspondingly low output and a corresponding
compressor; however, this would result in that the air conditioning
could be inadequate while driving.
[0012] However, even if the fuel cell and the compressor were
designed to be large enough, there would still be different
requirements with respect to different situations or also with
respect to different areas of the vehicle interior, so that for
this reason, the problems would not be adequately solved.
SUMMARY OF THE INVENTION
[0013] A primary object of the present invention is to devise a
system with an internal combustion engine, a fuel cell and a
climate control unit which, both in stationary operation and also
when driving, enables an operating mode in which the exhaust heat
of the fuel cell is optimally used.
[0014] A further object of the invention is to provide a system and
a process which is especially adapted to achieving air conditioning
both when the internal combustion engine is stopped and while
driving; in particular, such that it will also be possible to use
the system and process in an advantageous manner for heating the
vehicle interior or to act in a support role.
[0015] Another object of the invention is to devise a climate
control unit in which, even when stopped, heating operation is
possible, exhaust heat of a fuel cell being used and the climate
control unit being simple and economical.
[0016] The first object is achieved in accordance with the
invention by a system of the initially mentioned type in which
there are heat transfer means for transferring the exhaust heat of
the fuel cell to the heat transfer circuit and there are bridging
means for bridging the segment of the heat transfer circuit which
runs through the internal combustion engine so that an isolated
circuit is formed in the bridged operating state.
[0017] By the formation of an isolated circuit in accordance with
the invention, the heat transfer circuit can be configured
depending on the operating situation such that, when driving, the
exhaust heat of the fuel cell is transferred to the internal
combustion engine, or in stationary operation is available only for
the climate control unit for heating of the motor vehicle interior.
The transfer means are formed, in one advantageous embodiment, by a
3-way valve and a bypass line, the bypass line bridging all those
components which are not necessary in stationary operation,
especially the internal combustion engine, for avoiding heating of
its comparatively high mass.
[0018] The heat transfer means are formed in an especially simple
manner by a segment of the heat transfer circuit being routed
through the fuel cell.
[0019] In another advantageous version, the hot exhaust gas of the
fuel cell is routed via a heat exchanger which is accommodated in
the heat transfer circuit.
[0020] In a third advantageous version, the fuel cell is connected
to an afterburner for afterburning of the exhaust gas of the fuel
cell, the exhaust gas of the afterburner being routed via a heat
exchanger which is accommodated in the heat transfer circuit. The
second and third advantageous versions can be used especially for
solid oxide fuel cells (SOFC) since this type of fuel cell works at
very high temperatures and therefore, the exhaust gas is very
hot.
[0021] The climate control unit is advantageously equipped with a
heat exchanger for heating the vehicle interior, an electrical
heater connected to the fuel cell for power supply, and a first
evaporator of the cooling circuit. In this way, the climate control
unit can be easily used as an auxiliary heater since both the
generated electrical energy as well as the exhaust heat of the fuel
cell are supplied to the climate control unit to heat the motor
vehicle. By accommodating the evaporator of a cooling circuit, the
climate control unit can also be used as a stationary cooling
device, the electrical energy produced by the fuel cell being used
to operate the cooling circuit.
[0022] To operate the system in accordance with the invention as an
auxiliary cooling device, a heat exchanger is incorporated into the
isolated circuit for dissipating heat from the heat transfer
circuit. The heat exchanger can be the radiator of the internal
combustion engine or also a separate heat exchanger with
dimensioning which has been matched to operation of the isolated
circuit.
[0023] With regard to the second object, it is especially
advantageous to accommodate an additional compressor which is
mechanically driven by the internal combustion engine in the
cooling circuit, the electrically driven compressor and the
mechanically driven compressor being arranged redundantly and being
able to be turned on and off individually. Thus, when driving, the
mechanically operated compressor can be used to operate the cooling
circuit, while in stationary operation the electrically driven
compressor is active. The electrically driven compressor can also
be used to support the operation of the mechanically driven
compressor when driving.
[0024] To optimize the cooling circuit, in one advantageous
development, two component circuits are formed, the first component
circuit being formed by the first evaporator, the condenser and the
electrically driven compressor, and the second component circuit
being formed by the second evaporator, the condenser and the
compressor which is mechanically driven by the internal combustion
engine. Thus, individual areas of the motor vehicle can only be
cooled in stationary operation, while others are cooled only while
driving or while driving and while stopped.
[0025] As an alternative to the use of two compressors, a hybrid
compressor can also be used which can be driven both mechanically
by the internal combustion engine and also electrically with power
supplied by the fuel cell.
[0026] A system with two component circuits can be used especially
advantageously in a truck with a cab which has a rear and a front
area, the first evaporator being assigned to the rear area and the
second evaporator being assigned to the front area. In this way, it
is possible during different operating states of the motor vehicle
to individually control the climate of different areas of the
vehicle interior with different evaporators, and each of the
evaporators or the incorporation of each of the evaporators into
the overall system with respect to the respective situation or the
respective area of the vehicle interior can be optimized. Even if
this invention is described essentially using a system with a fuel
cell, it exhibits its advantages not only in this connection, but
also in conjunction with some other APU (auxiliary power unit)
which can be implemented in the simplest case, for example, as a
motor-driven generator.
[0027] It is especially useful for the first compressor to be
connected to a first evaporator and for the second compressor to be
connected to the second evaporator. The first evaporator which is
supplied with energy by the fuel cell can interact in this way with
an evaporator which is designed especially for the output of the
fuel cell which can be chosen preferably to be low. The second
compressor is matched to the second evaporator, and the two
components can be designed for the required climate control
performance.
[0028] Likewise it can be provided that the second compressor is
connected to the first evaporator. Therefore, for example, if the
first compressor interacts with the first evaporator while the
vehicle is stopped, it can still be useful, for example, for the
second compressor to interact with the first evaporator while
driving. In this way, it is then possible to avoid operation of the
fuel cell since the two evaporators interact with the same
compressor.
[0029] It can likewise be useful for the first compressor to be
connected to the second evaporator. This can be especially
preferable in the case in which a hybrid compressor is used as the
sole compressor. In this case, the hybrid compressor must perform
the compression work necessary for the air conditioning during all
driving situations and for all areas of the vehicle interior.
[0030] Furthermore, it is especially useful for the first
evaporator to be designed for cooling the sleeping compartment of a
commercial vehicle, especially for stationary air conditioning. The
first evaporator can thus be optimized with respect to the air
conditioning of the sleeping compartment. In general it can
therefore be designed to be correspondingly small.
[0031] In this sense, it is likewise useful for the second
evaporator to be designed for cooling the driver's compartment of a
passenger vehicle. Here, in general, higher air conditioning
performance is desired, so that a larger evaporator is used.
[0032] In another embodiment of the invention for cooling or
heating the interior of a motor vehicle, when stopped, the interior
is cooled with a second cooling circuit which is connected to the
first cooling circuit, a compressor being driven by means of
electrical energy from an APU or fuel cell. This will not preclude
the fact that the operating mode intended for stationary climate
control can also be used when driving. In this way, the advantages
and particulars of the system in accordance with the invention are
also realized within the framework of the process. This also
applies to the especially preferred embodiments of the process in
accordance with the invention described below.
[0033] In particular, the process in accordance with the invention
is advantageously developed in that there is a second compressor
which is driven by means of mechanical energy while driving.
[0034] Likewise it can be especially useful for the first
compressor to be a hybrid compressor.
[0035] It is also particularly useful for the first compressor to
interact with the first evaporator and for the second compressor to
interact with the second evaporator. It can likewise be provided
that the second compressor interacts with the first evaporator
and/or for the first compressor to interact with the second
evaporator.
[0036] The third object of the invention is obtainable using a
climate control unit which has a fan unit by which an air flow can
be produced for cooling the fuel cell and an electrical heating
unit being supplied with power by the fuel cell and by which the
air flow can be heated to heat the vehicle interior.
[0037] The climate control unit of the invention can be used
independently of the vehicle. Cooling of the fuel cell by an air
flow can be much more economical than by a liquid circuit. In
addition, the transfer of heat to an air flow which heats the
interior is eliminated since the air flow routed through the fuel
cell can be used directly to heat the vehicle interior.
[0038] In the additional, heating of the air flow by an electrical
heating unit which is powered by the fuel cell allows the energy
generated in the fuel cell to be used twice. On the one hand, the
generated current in the electrical heating unit is converted into
heat, and on the other hand, the exhaust heat produced in the
generation of current is likewise used for heating of the vehicle
interior. Since only low power need be produced by this separate
fuel cell for the climate control unit, cooling with air is
sufficient and the fuel cell is not overheated.
[0039] Furthermore, it is advantageous that the climate control
unit can also be used for operating a cooling circuit. The
generated electrical current is used to drive a compressor. The
exhaust heat produced by the fuel cell in this operating mode is
not routed into the vehicle interior, but dissipated to the
outside. In this way, a cooling operation is possible when the
vehicle engine is turned off.
[0040] In another version of the climate control unit of the
invention, the air flow routed through the fuel cell is not routed
directly into the vehicle interior, but the heat is transferred in
a heat exchanger to a flow of fresh air.
[0041] In one advantageous embodiment of a climate control unit in
which a cooling function is also implemented, the cooling circuit
has an electrically driven compressor and a mechanically driven
compressor which are located parallel to one another. The
mechanically driven compressor is therefore used when driving,
while the electrically driven compressor when stopped is used to
operate the cooling circuit or can be used while driving for
supporting the mechanical compressor.
[0042] The invention is based, in part, on the finding that,
especially for climate control of the sleeping compartment of a
commercial vehicle, the energy from the fuel cell can be
advantageously used. The fuel cell can be designed to be
correspondingly small as a result of the low power consumption.
High climate control performance while driving can be made
available by other energy sources.
[0043] The invention is described in detail below with reference to
the embodiments illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 shows a simplified schematic of a system in
accordance with the invention;
[0045] FIG. 2 shows a first embodiment of a system in accordance
with the invention with a cooling circuit with an electrically
driven compressor;
[0046] FIG. 3 shows a modification of the embodiment from FIG. 2
with an additional mechanically driven compressor,
[0047] FIG. 4 shows another modification of the embodiment from
FIGS. 2 & 3 with a cooling circuit which has two component
circuits,
[0048] FIG. 5 shows a modification of the embodiment from FIG. 4
with a hybrid compressor,
[0049] FIG. 6 shows a second embodiment of a system in accordance
with the invention with a SOFC fuel cell,
[0050] FIG. 7 shows a modification of the embodiment from FIG.
6,
[0051] FIG. 8 is a schematic connection diagram of another
embodiment of the system of the present invention;
[0052] FIG. 9 is a schematic connection diagram of another system
in accordance the invention;
[0053] FIG. 10 is a schematic connection diagram of yet another
system in accordance with the invention;
[0054] FIG. 11 is a schematic connection diagram of a further
system in accordance with the invention
[0055] FIG. 12 shows an embodiment of a climate control unit of the
invention with a direct air supply;
[0056] FIG. 13 shows another embodiment of a climate control unit
in accordance with the invention with heating via a heat
exchanger;
[0057] FIG. 14 shows a further embodiment of a climate control unit
of the invention with a cooling circuit which has two
compressors.
DETAILED DESCRIPTION OF THE INVENTION
[0058] FIG. 1 shows a system in accordance with the invention in a
simple schematic. While driving, a climate control unit 3, a PEM
fuel cell 4 and an internal combustion engine 2 are joined together
in a heat transfer circuit 1. Both the heat produced in the
internal combustion engine 2 and also the heat produced in the fuel
cell 4 are transported via the heat transfer circuit 1 to the
climate control unit 3 which can use the heat for heating of the
vehicle interior via a suitable heat exchanger. Between the fuel
cell 4 and the internal combustion engine 2, there is a 3-way valve
24 which is designed to interrupt the connection between the fuel
cell 4 and the internal combustion engine 2 in the heat transfer
circuit 1 and instead to bridge the segment 6 of the heat transfer
circuit 1 which runs through the internal combustion engine 2 by a
bypass line 5. The coolant is circulated therefore in the resulting
isolated circuit only through the fuel cell 4 and the climate
control unit 3. A pump which provides for circulation is not shown
in FIG. 1, but of course is provided at a suitable location. The
term "fuel cell" used here is defined as an entire fuel cell system
which also comprises the secondary assemblies for supplying a
suitable fuel. The exact progressions of the inner processes in the
fuel cell are not important to the invention and are therefore not
explained in detail.
[0059] The heat transfer circuit 1 with the incorporation of the
internal combustion engine 2 is intended mainly for operation while
driving, while use of the isolated circuit without the internal
combustion engine 2 is intended mainly for stationary operation.
However, mixed operation is also possible, in which the coolant
flow is divided into line segments 6, 5 in order, for example, at
the start of driving not to dissipate too much heat from the
internal combustion engine 2, but nevertheless to achieve
sufficient heating action.
[0060] The climate control unit 3 is set up in a simple version
only to heat the vehicle interior, but can also be expanded by a
cooling circuit so that there are both a heating and cooling
function by the climate control unit 3.
[0061] FIG. 2 shows a more detailed representation of the system
from FIG. 1. The heat transfer circuit I is not shown completely by
the internal combustion engine 2 and the segment 6 of the heat
transfer circuit 1 which runs through it being omitted. In the
segment of the heat transfer circuit 1 which is used in any case
and through which coolant flows both while driving and when stopped
there is a pump 25. The climate control unit 3 is shown in greater
detail in FIG. 2 and has a heat exchanger 7 for heating the vehicle
interior. Moreover, there is an electrical heater 8 which is
supplied by the fuel cell 4, and for this reason, is connected to
it. When driving, it is of course unnecessary for the electric
heater 8 to be supplied solely by the fuel cell, but supply can
also take place from another energy source of the vehicle
electrical system. It is also possible that during the starting
phase of the fuel cell, when it cannot yet make available full
power, the fuel cell is supported by the vehicle battery.
[0062] The climate control unit 3 from FIG. 2 is equipped with a
cooling circuit 10 which comprises an evaporator 9, a compressor
11, a condenser 15 and a control valve 26. Liquid coolant is
evaporated in the evaporator 9. The heat which is necessary for
this purpose is removed from the vicinity of the evaporator 9 so
that it is cooled. In the function of a climate control unit for
motor vehicles, the hot air is received either, for example, from
the vehicle interior or from the outside and is blown into the
vehicle interior as cooled air. The coolant which leaves the
evaporator 9 under low pressure and in vapor form is compressed by
the compressor 11. The now highly superheated steam is supplied to
the condenser 15, where it condenses and leaves the condenser 15 as
liquid coolant. The condenser 15 likewise requires a fan for its
operation, which is however not shown in FIG. 2 for the sake of
clarity. The circuit is thus closed.
[0063] The compressor 11 of the cooling circuit 10 is driven
electrically. The electric motor which is used is supplied by the
fuel cell 4. Of course, it is also possible for not only the
compressor 11 or the electrical heater 8 to be supplied from the
fuel cell 4, but for other consumers 22 to also be connected to the
fuel cell 4 and to be supplied at the same time.
[0064] In stationary operation, as stated above, the segment 6 of
the heat transfer circuit 1 which runs through the internal
combustion engine 2 is bridged by the bypass line 5. In stationary
heating operation, the heat produced by the fuel cell 4 is used to
heat the vehicle interior so that the generated heat can be
adequately dissipated. In stationary cooling operation, the current
produced by the fuel cell is used to operate the compressor 11, but
the exhaust heat generated by the fuel cell 4 cannot be dissipated
via the vehicle heating system. Therefore, in the bypass line 5,
there is another heat exchanger 12 which dissipates the excess heat
from the heat transfer circuit 1. Thus, the heat exchanger 12 has a
fan which ensures adequate operation of the heat exchanger 12 even
when stationary.
[0065] Another alternative is not to activate the bypass line 5
during stationary cooling, but to use the entire heat transfer
circuit 1 with the segment 6 which runs through the internal
combustion engine. The exhaust heat of the fuel cell 4 is routed
via the engine and the radiator assigned to it, where the heat is
dissipated.
[0066] FIG. 3 shows a modification of the system from FIG. 2. In
contrast to FIG. 2, in the cooling circuit 10 there are two
compressors 11 and 17. The compressor 11 is, in turn, an
electrically driven compressor which is connected to the fuel cell
4 for this purpose, while the compressor 17 is mechanically driven
by the internal combustion engine. The compressor 17 is sufficient
for operating the cooling circuit 10 while driving. The fuel cell 4
could therefore be turned off. However, there are operating
situations in which heavy loading of the internal combustion engine
by the compressor 17 is to be avoided, for example, because power
is to be fully available for driving the motor vehicle, so that it
is a good idea to connect the electrically operated compressor 11
in parallel so that compression of the vaporous coolant is managed
jointly by the two compressors. The two compressors can be turned
on and off individually by the two check valves. The mechanical
compressor 17 can therefore also be turned off completely and the
electrical compressor 11 manages the task in the cooling circuit 10
alone. This is especially advantageous when stationary cooling
operation is to be enabled; the mechanical driving of the
compressor 17 is therefore omitted.
[0067] The embodiment shown in FIG. 4 is suitable for an
application in which a cooling circuit has a front system and a
rear system. Accordingly two component circuits 13, 14 are formed.
The first component circuit 13 comprises the first evaporator 9,
the electrically driven compressor 11 and the condenser 15., The
evaporator 9 is thus assigned to the rear system, therefore cooling
the rear area of the vehicle. The second component circuit 14
comprises a second evaporator 16, a mechanically driven compressor
17, and a condenser 15. The second evaporator 16 is assigned to the
front system, therefore cooling the front area of the motor
vehicle.
[0068] While driving in a truck, typically, only the front part of
the cab is used, accordingly only the second evaporator 16 is
necessary for cooling. In this operating mode, the internal
combustion engine is in operation and can drive the mechanically
driven compressor 17. In stationary operation, conversely, the rear
part of the cab, where the sleeping area is located, is to be
cooled. This area is the responsibility of the first evaporator 9
to which the electrically driven compressor 11 is assigned. In
stationary operation, the internal combustion engine is not
running, but the fuel cell 4 is in operation and can supply the
electrically driven compressor 11 with current. The two component
circuits can be connected to one another via valves so that the two
compressors 17, 11 work redundantly. Two control valves 27, 28
control the output of the two component circuits 13, 14.
[0069] In the embodiment from FIG. 5, instead of the two
compressors, one being driven electrically and the other
mechanically driven, a so-called hybrid compressor 20 is used. It
can be driven both by an electric motor which is supplied by the
fuel cell 4 and also mechanically by the internal combustion
engine. In this embodiment, two component circuits 18, 19 are
formed, the first evaporator 9 being assigned to the rear system
and the second evaporator 16 being assigned to the front system. A
control 21 triggers the hybrid compressor 20 such that, when
driving, it is mechanically driven by the internal combustion
engine, and when stationary, it is electrically driven by the
electric motor which is supplied by the fuel cell 4. If a
mechanical drive possibility of the compressor 20 is to be omitted
as a result of the vehicle concept, instead of the hybrid
compressor, an electrically driven compressor can also be used.
[0070] The incorporation of the fuel cell 4 into the heat transfer
circuit 1 as shown in FIGS. 1 to 5 is especially suited for
so-called PEM (proton exchange membrane) fuel cells since they work
at a comparatively low temperature.
[0071] In the embodiment of FIGS. 6 & 7, conversely, a
so-called SOFC fuel cell (solid oxide fuel cell) is used. These
fuel cells work at a much higher temperature. Instead of
incorporating the fuel cell directly into the heat transfer circuit
1, the exhaust heat of the SOFC fuel cell arrangement 34 is
dissipated via the anode exhaust gas 31 and the cathode exhaust 32.
They are supplied to an afterburner 36, for example, a catalytic
afterburner, toxic components, such as carbon monoxide, being
re-burned and leaving the afterburner 36 as harmless exhaust gas
33. This gas flow which has been heated further flows through two
heat exchangers 37, 38, in the first heat exchanger 37, the fuel 42
being preheated and supplied to the fuel cell arrangement 34, and
air 41 being preheated in the second heat exchanger 38, which air
is likewise supplied to the fuel cell arrangement 34. The air 41 is
compressed beforehand by a compressor 39. However, the exhaust gas
33 of the afterburner 36, after passing through the two heat
exchangers 37, 38, still has such a high temperature that this heat
can be transferred in another heat exchanger 35 to the heat
transfer circuit 1. The heat transfer circuit 1 is, in turn, made
such that an isolated circuit can be formed with the bypass line 5.
In stationary heating operation, therefore, the fuel cell 34 heats
the coolant in the heat heat can be transfer circuit 1 via its
exhaust gas which has been burned in the afterburner 36, so that
this heat can be decoupled in the climate control unit 3 for
heating of the vehicle interior.
[0072] In turn, a cooling circuit 10 is shown schematically which
can be added to the climate control unit 3 for making available the
possibility of motor vehicle cooling.
[0073] The SOFC fuel cell arrangement 34 contains an integrated
reformer by which a hydrogen-containing gas which is burned in the
actual fuel cell to generate current is produced from the fuel
which is ordinarily carried, such as gasoline or diesel. For
satisfactory operation of the reformer, it is necessary for
preliminary reactions to take place in a pre-reformer before fuel
supply. In doing so, for example, long diesel molecule chains are
decomposed into shorter molecule chains, For these preliminary
reactions, a relatively high temperature is necessary, so that the
exhaust heat of the fuel cell 34 is also used in the embodiment
from FIG. 6 to heat the pre-reformer 30. The fuel or the fuel
mixture leaves the pre-reformer 30 with a temperature of roughly
600.degree. C.
[0074] In addition, in the system shown in FIG. 6, there is a water
tank 40 which is used to humidify the supplied fuel 32; this
improves reforming to produce the hydrogen-containing gas.
[0075] The electrical current produced by the fuel cell 34 can be
used both for an electrical compressor 11 of the cooling circuit 10
and also for other electrical consumers 22 or charging of a battery
23.
[0076] In the modified version from FIG. 7, the exhaust gas of the
catalytic afterburner 36 is routed in parallel to the two heat
exchangers 37, 38, so that an exhaust gas with a higher temperature
is available to preheat the supplied air 41. In addition, there is
no pre-reformer, but the exhaust gas 31 of the fuel cell 41 is
supplied again directly to it.
[0077] FIG. 8 shows a schematic connection diagram of the system of
the invention having a first cooling circuit 110 in which there are
a first compressor 112, a condenser 114, an expansion element 116
and a first evaporator 118. The compressor 112 is supplied with
power by a fuel cell 120. In this way, heat energy can be removed
from the space surrounding the evaporator or 18 by the evaporator
18. Furthermore, a second cooling circuit 124 is implemented which
has a second compressor 126 and a second evaporator 122. Other
components of the second cooling circuit 124 are the condenser 114
which has already been mentioned in conjunction with the first
cooling circuit 110, and the corresponding expansion element 116.
The second evaporator 122 can remove heat from the space
surrounding it by operating this cooling circuit.
[0078] These components can now interact in a diverse manner that
can be influenced or set by the solenoid valves 140, 142 and other
switching components.
[0079] For example, it is possible that, while driving the motor
vehicle, only the second cooling circuit 124 is operated,
specifically by the compressor 126 being supplied by the energy of
the internal combustion engine. The evaporator 122 can, for
example, remove heat from the driver's compartment and thus air
condition it. When the vehicle is stopped, it can be useful, for
example, for only the first compressor 112 to be operated so that,
for example, heat is removed from the sleeping compartment of the
motor vehicle by the evaporator 118.
[0080] FIG. 9 shows a schematic connection diagram of another
version of the system in accordance with the invention. With
respect to the cooling circuits 110, 124, this embodiment of the
system is identical to the embodiment which is shown in FIG. 8. In
addition, the fuel cell 120 can run an electrical heater 128 which
can deliver heat into the area in which, during cooling operation,
the first evaporator 118 is active. For example, the sleeping
compartment of a truck can be heated in this way on cold nights via
the fuel cell. In order to use the exhaust heat of the fuel cell
120 in addition, the exhaust heat is likewise sent via the engine
cooling circuit or an isolated circuit 130 bypassing the engine to
the heat exchanger 132, from where it travels into the sleeping
compartment, using a bypass similar to the bypass 5 of the circuits
of FIGS. 1-7.
[0081] FIG. 10 shows a schematic connection diagram of another
system in accordance with the invention. With respect to the
heating function, FIG. 10 is identical to the embodiment which was
described in FIG. 9. The cooling circuits 110, 124 are made
differently. There is only one compressor 112 which is made either
as an electrical compressor or as a hybrid compressor, i.e., it can
be electrically and mechanically driven. The two evaporators 118,
122 can be selectively used by suitable fluid guidance in this way
so that ideal climate control conditions can be achieved
individually depending on the situation or for different areas of
the motor vehicle.
[0082] FIG. 11 shows a schematic connection diagram of another
system in accordance with the invention. The solid lines show a
first cooling circuit 110 and a second cooling circuit 124. The
first cooling circuit 110 contains a compressor 112 which is
supplied with energy by a fuel cell 120. The second cooling circuit
124 is supplied with mechanical energy by the internal combustion
engine 138 of the motor vehicle. The cooling circuits 110 and 124
share the condenser 114, the expansion element 116 and the
evaporator 122. In this way, the invention can also be used in a
motor vehicle with only one evaporator 122, selectively, one or the
other of the compressors 112, 126 being operated. Depending on the
operating mode, the valve 136 is set accordingly. The system can be
used to benefit in this configuration in a truck or in a commercial
vehicle. The broken line shows that the system can be easily
combined with another evaporator 118 with its own expansion element
34. The evaporator 122 can be used in the already described manner
especially for air conditioning of the sleeping compartment of a
commercial vehicle.
[0083] The climate control unit shown in FIG. 12 is suited both for
heating and also for cooling a vehicle interior. The energy
necessary both for heating and cooling the vehicle interior is made
available by a fuel cell 201. The fuel cell type used in this
embodiment is preferably a PEM-FC (proton exchange membrane fuel
cell), since the operating temperature of this fuel cell is well
suited for air cooling of the fuel cell and heating of the vehicle
interior.
[0084] The fuel cell 201 is built such that air can flow through
it. To produce an air flow, there is a fan unit 204. The air flow
produced by it absorbs the exhaust heat of the fuel cell 201 and
leaves the fuel cell again. In heating operation of the climate
control unit shown, the air flows subsequently through the
electrical heating unit 205 which is supplied by the current
produced by the fuel cell. The air which has been preheated by the
exhaust heat of the fuel cell is therefore additionally heated
again by the electrical heating unit 205. To transfer the heat
which is produced by the fuel cell 201 and the electrical heating
unit 205 to the vehicle interior, heat transfer means 200 is
provided. In the simplest case, the heat transfer means 200 is
formed by an air guide which guides the heated air directly into
the vehicle interior 3.
[0085] To control the heat flow which is supplied to the vehicle
interior 203, there are several possibilities. The first
possibility is to change the output of the electrical heating unit
205. At the same time, the fuel supply to the fuel cell 201 would
have to be adapted. The second possibility is to vary the air flow
which is produced by the fan unit 204. However, in doing so, it
must be watched that heat dissipation from the fuel cell 201 is
sufficient so that the maximum allowable operating temperature is
not exceeded. It must always be watched that the parameters in
producing the heat flow are linked to one another, i.e., the
intensity of the air flow, the amount of electrical energy
produced, and the output of the electrical heating unit 205 are
linked to one another and cannot be regulated without the other
parameters being adapted accordingly.
[0086] Another possibility for changing the heat flow entering the
vehicle interior 203 is to divert part of the heated air to the
outside. To do this, in FIG. 12, there is a flap 214 which can be
pivoted such that the air cannot reach the vehicle interior 203 or
only part of it can do so and the other part is released to the
outside. Discharging the hot air to the outside can be necessary
when the climate control unit or heating system of the vehicle
interior is to be turned off suddenly, but cooling is still
necessary for dissipating the heat generated or still stored in the
fuel cell. Moreover, a case of operation is possible in which very
low heat output is desirable, but the fuel cell delivers a minimum
output during operation that is greater than the required power for
the heating of the vehicle interior 203.
[0087] Normally, in climate control units of this type, rapid
control of the heat output is not critical. One advantageous use
is, for example, for heating the sleeping compartment in trucks.
The sleeping compartment is comparatively small and the temperature
desired there is not very high. Therefore, low heat output is
sufficient. Since it can be planned long beforehand when the
desired temperature is to be reached, there can be a comparatively
long heating time until the desired room temperature is reached. To
maintain the room temperature, likewise a low heat output is
necessary. The small required heat output also enables, first of
all, the advantageous configuration of the fuel cell 201 as an air
cooled system. For larger outputs, it would no longer be possible
to ensure sufficient cooling by air. Based on the air cooling, the
climate control unit is made very compact and can be operated as an
independent component without the other means of the vehicle
infrastructure having to be included. For example, the climate
control unit could be made as a module that can be inserted into a
suitable drawer area in the cab of a truck.
[0088] The climate control unit of the invention can be easily
expanded such that stationary cooling operation is possible, i.e.,
with the vehicle engine turned off. To do this, the described fuel
cell is coupled to a cooling circuit 207. Cooling circuits, in the
illustrated embodiment, require a compressor 208 by which a
vaporous coolant is compressed. In a downstream condenser 211, the
pressurized coolant vapor condenses. In the evaporator 212, the
cooling liquid evaporates, the cold produced by evaporation being
used to cool the air supplied to the vehicle interior 203. Then,
the vaporous cooling liquid is re-compressed by the compressor 208.
At a suitable location of the cooling circuit 207, there is
generally a control valve 213 to regulate the operation of the
cooling circuit.
[0089] In known climate control units, the compressor of the
cooling circuit is driven either mechanically or electrically. In
stationary operation, there is the problem that the cooling circuit
cannot be operated if the engine of the vehicle is not running. In
an electrically operated compressor, stationary operation is
theoretically possible, but the length of operation depends on the
capacity of the battery. Even in high-capacity batteries, cooling
operation over a longer time is not possible.
[0090] In the climate control unit of FIG. 12, the electrical
compressor 208 of the cooling circuit 207 is supplied with power
from the fuel cell 201. In this way, the cooling circuit 207 can
also be operated during longer stationary times without the need
for the vehicle engine to be in operation. In cooling operation,
the fan unit 204 of the climate control unit runs in order to cool
the fuel cell 201. The generated current is not made available to
the electrical heating unit 205, but is used to operate the
electrical compressor 208. The air heated by the fuel cell 201 is
not supplied in the above described manner to the vehicle interior
203, but is discharged to the outside by opening of the flap
214.
[0091] Of course, the electrical current produced by the fuel cell
201 can be used not only for operating the heating unit 205 or the
compressor 208, but can also be used for other vehicle components
such as, for example, interior vehicle lights or a radio
system.
[0092] FIG. 13 shows a another embodiment of a climate control unit
in accordance with the invention. In the version shown here, the
air which is heated as the fuel cell 201 is cooled is not routed
directly into the vehicle interior 203, but instead, the air is
routed through a heat exchanger 206 and then to the outside. To
heat the vehicle interior 203, there is a second air flow which is
produced by a second fan 210 and which is likewise routed via the
heat exchanger 206. The air guides are designed such that the two
air flows cannot mix. In the direction of the vehicle interior, the
heat exchanger 206 is connected upstream of the electrical heating
unit 205 which is operated, as in the embodiment of FIG. 12, by the
electrical energy produced by the fuel cell 201.
[0093] The advantage of the arrangement described here is that, on
the one hand, an odor which forms in the fuel cell 201 is prevented
from being transferred to the vehicle interior, and on the other
hand, it is ensured that a leak in the fuel cell 201 cannot lead to
toxic gases entering the vehicle interior. Another advantage is
that, by separating the air flows, the amount of air reaching the
vehicle interior 203 can be adjusted independently of the cooling
of the fuel cell 201 by the second fan 210 being operated as is
optimum for heating of the vehicle interior 203.
[0094] The embodiment shown in FIG. 13 also has the potential for
operating the electrical compressor 208 of the cooling circuit 207
in order to thus enable stationary cooling when the engine of the
motor vehicle is not in operation.
[0095] FIG. 14 shows one development of the embodiment from FIG.
12. In this embodiment, in the cooling circuit 207 there are two
compressors, one electrical compressor 208 which is supplied by the
fuel cell 201, and a mechanical compressor 209 which is operated,
for example, by the internal combustion engine of the motor
vehicle. The two compressors are located in part parallel to one
another so that the cooling circuit can be operated either with the
electrical compressor 208 or the mechanical compressor 209 or there
can be parallel operation of the two compressors, similar to the
arrangement of the FIG. 3 embodiment. Via the two valves 215, 216
each of the indicated configurations of the cooling circuit 207 an
be adjusted.
[0096] While driving, the mechanical compressor 209 is in
operation. The fuel cell 201 need not be turned on. Only in the
case of operation when power is not to be taken from the internal
combustion engine to operate the cooling circuit 207, is the fuel
cell 201 additionally started up in order to support or replace the
mechanical compressor 209 by the electrical compressor 208. In
stationary operation with the engine turned off, only the
electrical compressor 208 is operated via the fuel cell 201.
* * * * *